Aristotle's Metaphysics deals with what he referred to as "primary philosophy" or "first principles." The field of metaphysics studies cosmology and ontology, and in Aristotle's Metaphysics, both areas are investigated through an analysis of the nature of being. Cosmology is concerned with the origin and nature of the universe, and ontology with the nature of existence.
Aristotle refers to the philosophical inquiry into ethics and politics as "practical science," as it is concerned with the individual's actions. His Nicomachean Ethics, often referred to simply as the Ethics, offers a close study of Greek ideals, of the notion of "the good" and the best way of life, of the nature of virtue, and of social problems and conflicts. The shorter Eudemian Ethics covers similar material but with different emphases. Politics approaches political science from the viewpoint of the state, or city-state. Consisting of eight books (the order of which is still a matter of debate), Politics covers such topics as the nature and structure of the state and of society, civic virtue, education, and class roles and distinctions.
Little is known about the fate of Aristotle's works after his death. It is believed by some scholars that for about two hundred years the works were either lost or hidden. They were discovered by Sulla (178-38 B.C.) and brought to Rome. Modern editions of Aristotle's works derive from Roman editions dating back to the late first century B.C. In the Middle Ages, Latin and Arabic translations broadened the influence of Aristotle's teachings and his philosophy was studied extensively by St. Thomas Aquinas (c. 1225-74) and later by Francis Bacon (1561-1626). As relatively few of Aristotle's works can be dated with any degree of accuracy, the focus of nineteenth- and twentieth-century scholars has been on determining the chronological order of the works.
Modern criticism of Metaphysics has focused on Aristotle's intended meaning, as well as on the identification of, and attempts to resolve, apparent inconsistencies within the text. Joseph Owens has discussed the various interpretations regarding the nature of being made by medieval metaphysicians, noting that there are two distinct ways in which this doctrine may be understood. Owens has observed that medieval Christian thinkers attempted to unify these two concepts; he has also presented the views of later critics who either attack or support such a unification. Franz Brentano has examined a different aspect of the nature of being, studying Aristotle's analysis of "potential" and "actual" being. Brentano has pointed to some apparent difficulties with the definitions Aristotle provides, and has offered an interpretation which elucidates the two concepts and the relationship between potential and actual being. The concepts of substance and form as Aristotle presents them in Metaphysics have also generated much criticism. Wilfrid Sellars and Richard Rorty have both approached these issues, but from different angles. Sellars has noted the ways in which Aristotle's Categories (discussed in the Science section of this volume), particularly the theory of predication found there, can aid one's understanding of the nature of substance, form, and matter as presented in Metaphysics. Rorty has argued that, by giving more credence to Aristotle's claim that genus is matter, the difficulties encountered when studying substance and form are reduced.
The most salient issues for modern critics with regard to Ethics have included Aristotle's doctrine of "the good" and the related issue of happiness—"the good" being the single end at which one aims throughout one's life, and happiness being a result of that quest. W. F. R. Hardie and Daniel T. Devereux have addressed the critical debate concerning the nature of the good and whether Aristotle views it as a dominant or inclusive end. Hardie has asserted that Aristotle presents the final good as dominant, but that the philosopher at the same time suggests its inclusive nature. Hardie has concluded that the doctrine of the good focuses on the power of man to "reflect on his own abilities and desires and to conceive and choose for himself a satisfactory way of life." Devereux has asserted, however, that the issues of dominance and inclusiveness are far removed from Aristotle's views on the subject of the good. Devereux has stated that the Ethics outlines two different types of happiness, both of which are "implicitly inclusive." Perfect happiness, Devereux has noted, is associated by Aristotle with a life of philosophical contemplation, and a secondary degree of happiness may be achieved through a life of moral virtue. Aristide Tessitore has also stressed Aristotle's proposition that perfect, complete happiness can only be found through philosophic contemplation. Yet Tessitore has emphasized as well that Aristotle encourages a life of virtue for non-philosophers by linking them, through the concept of moral decency, to philosophers.